N-vinyl-2-pyrrolidone and its polymer, poly(N-vinyl-2-pyrrolidone) (PVP), is a water soluble and biocompatible polymer that has been widely used for a range of commercial applications including for tablet binding, hair fixation, wetting agents in ophthalmic lens formulations, membranes, adhesives, hydrophilic coatings, etc. Several methods for preparation of functionalized polyvinylpyrrolidones have been reported, for instance using azo radical initiators in the presence of chain transfer agents (e.g., mercaptoethanol, isopropanol, isopropoxyethanol, mercaptoethylamine, mercaptopropionic acid). See e.g. U.S. Pat. No. 5,135,297 (SURFACE COATING OF POLYMER OBJECTS); U.S. Pat. No. 6,756,449 B2 (AND BLOCK COPOLYMERS CONTAINING POLY (VINYL PYRROLIDONE) UNITS, MEDICAL DEVICES, AND METHODS); and US 2005/0119404 A1 (PROCESS FOR THE PREPARATION OF AMPHIPHILIC POLY (N-VINYL-2-PYRROLIDONE) BLOCK COPOLYMERS). The disclosure of each of these documents is included herein by reference.
It is desirable in some cases to build functionality into the PVP to prepare materials that will be retained permanently in the final functional polymer device without leaching of the PVP component during use. For instance, (meth)acrylated or (meth)acrylamide functionalized PVP derivatives will find utility in contact lens compositions. In practice, during irradiation or thermal polymerization of the contact lens mix, the functional PVP will be covalently bonded into the crosslinked network and provide a non-leachable wettable ophthalmic lens.
Copolymers that incorporate silicone (PDMS) blocks and hydrophilic moieties such as PVP, poly(dialkylacrylamide) (e.g. polydimethylacrylamide, polyN-isopropylacrylamide and the like), and polyalkyleneglycol should compatibilize the hydrophobic and hydrophilic components of a contact lens formulation generating optically clear and functional lenses. These copolymers would be useful as active components in applications such as silicone hydrogel lenses. In addition, amphiphilic moieties will also find use in lens care solutions targeted for specific types of contact lens. Besides ophthalmic and lens care solutions, other applications for the amphipathic block copolymers include use in tissue engineering, transdermal implants and wound dressings, industrial adhesives, sealants, surface protecting agents, drug release agents and other biomedical applications.